Plasma reactor having divided electrodes

Abstract

A plasma reactor for generating a plasma for use in depositing a thin film on a large area wafer, such as in the manufacturing of solar cells. A plasma electrode unit in the plasma reactor is divided into a plurality of discrete electrodes, and RF electric power is sequentially applied to the divided plasma electrodes in accordance with a phase angle detected by a phase control unit. The sequential application of high frequency RF power across the divided plasma electrode unit resolves a standing wave problem in the plasma applied over a large area corresponding to a large area wafer.

What is claimed is: 
     
         1 . A plasma reactor for generating plasma, the plasma reactor comprising:
 a buffer chamber;   a divided plasma electrode unit comprising plural discrete electrodes and disposed within the buffer chamber;   at least one process gas inlet for receiving a respective process gas and for injecting the respective process gas into the buffer chamber proximate the discrete electrodes;   a process chamber in which a plasma can be formed by the discrete electrodes selectively energizing the process gas;   a substrate support disposed at a lower end of the process chamber for supporting a substrate onto which the plasma is deposited;   an RF electric power unit for supplying RF electric power; and   a phase control unit for sequentially applying RF electric power, received from the RF electric power unit, to each of the discrete electrodes of the divided plasma electrode unit.   
     
     
         2 . The plasma reactor of  claim 1 , wherein the phase control unit associates each discrete electrode of the divided plasma electrode unit with a phase angle or range of phase angles of the RF electric power, detects the phase of the RF electric power received from the RF electric power unit, and selectively applies the RF electric power to the discrete electrode of the plasma electrode unit associated with the detected phase angle of the RF electric power. 
     
     
         3 . The plasma reactor of  claim 2 , wherein
 the divided plasma electrode unit includes a first plasma electrode, a second plasma electrode, a third plasma electrode, and a fourth plasma electrode that are spaced apart from each other in a substantially horizontal plane, and   the phase control unit sequentially associates the each discrete electrode of the divided plasma electrode unit with one of the phase angles of substantially 0° (360°), 90°, 180°, and 270° of the RF electric power.   
     
     
         4 . The plasma reactor of  claim 1 , wherein the discrete electrodes of the divided plasma electrode unit are:
 spaced apart from each other in a substantially horizontal plane;   arrayed in correspondence with a shape of a wafer to be disposed on the substrate support; and   are insulated from each other through an insulator.   
     
     
         5 . The plasma reactor of  claim 1 , wherein the at least one process gas inlet comprises plural process gas inlets, each process gas inlet being associated with a respective one of the plural discrete electrodes. 
     
     
         6 . The plasma reactor of  claim 5 , further comprising:
 a partition wall extending downward from the top of the buffer chamber and between the plural discrete electrodes within the buffer chamber for isolating the process gases from each other, the buffer chamber is downwardly open to allow the process gases to be energized by the respective discrete electrodes and to form the plasma therefrom within the process chamber.